In an effort to avoid the disadvantages inherent in manually opening bales of fiber, such as cotton, and delivering fiber plucked from such bales to hoppers or the like for subsequent processing (e.g. blending), apparatus has been developed for mechanically carrying out these functions, an example of such mechanical apparatus being disclosed in U.S. Pat. No. 3,777,908, issued to Keller.
Such apparatus generally includes an elevated trackway located at the periphery of a bale laydown including a plurality of bales arranged in a desired pattern behind a plurality of hoppers or conveyor belt stations. As explained in greater detail in the aforementioned U.S. Pat. No. 3,777,908, a crane or frame is mounted on the elevated trackway for movement therealong above the bale laydown and this crane includes tracks extending along the length thereof for supporting a carriage or dolly that is arranged to move selectively along the crane tracks. A pick-up head is mounted on the dolly for selective vertical movement with respect thereto, and this pick-up head includes cooperating finger elements or tongs which can be selectively opened and closed to pick up a predetermined quantity of fibers from bales in the laydown.
In a commercial embodiment of the aforementioned apparatus, an automatic control system is provided for selectively moving the crane and dolly to any of a plurality of locations directly above the designated bale positions in the bale laydown, and the pick-up head is then lowered until a bale at any such designated position is engaged by a sensor asociated with the pick-up head, whereupon the finger elements close to remove a quantity of fiber from the bale and the pick-up head is raised and carried to a hopper or conveyor by the coordinated movement of the crane and dolly. This control system includes a plurality of cams fixed on the trackway and on the crane tracks at predetermined locations, and the crane and dolly are provided with switches arranged to be tripped by particular cams. An electronic control circuit is provided to automatically direct and coordinate movement of the crane along the trackway and the dolly along the crane tracks until the switches thereon are tripped by designated track and trackway cams, whereupon the crane and dolly will stop and thereby locate the pick-up head directly above a designated bale from which it is desired to remove fibers. The control system then causes the pick-up head to be lowered until the sensor engages the designated bale as aforesaid, after which the control system causes the crane and dolly to carry the pick-up head to a hopper or conveyor location at which the fibers are released by the pick-up head. It will be appreciated that the trackway cams and the crane track cams are located so as to permit the control system to move the crane, dolly and pick-up head to a position above any particular bale in the bale laydown, and the control system may be programmed to have the pick-up head remove fibers from any such bale in the bale laydown for delivery to any hopper or conveyor associated with such bale laydown.
While the normal operation of the aforementioned apparatus has been found to be quite satisfactory, it has been determined that on rare occasions malfunctions occur in the operation of the apparatus which can create dangerous situations, both in terms of damage to the apparatus itself and in terms of injury to any personnel who may be working in the vicinity of the apparatus. When it is recognized that the aforementioned apparatus is very large and expensive to produce, it will be appreciated that any damage or injury which is caused by a malfunction of the equipment is likely to be severe. For example, if the crane should become derailed, the apparatus could actually fall from the elevated trackway and cause significant damage to the apparatus as well as create a substantial hazard to anyone in the adjacent work area.
The present invention provides a safety system for apparatus of the aforementioned type which is designed to provide a recognizable indication that any one of a number of possible malfunctions has occurred, and to either stop further operation of the apparatus or provide corrective control measures therefor which will prevent damage to the apparatus or injury to personnel.